Sanding machine



Dec. 14, l1948.

L.. 1 RoTHRocK SANDING MACHINE 8 Sheets-Sheet 1 Filed April l1, 1947Dec. 14, 1948. 1 L.. RoTHRocK 2,456,217

SANDING MACHINE Filed April 11, 1947 e sheets-sheet 2 mi@ NN.

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8 sheets-sheet v5 Filed April 11. 1947 I 8 Sheets-Sheet 6 L. L. ROTHROCKSANDING MACHINE Dec. 14, 1948.

Filed April 11, 1.947

l.. 1 Ro'rHRocK 2,456,217

SANDING MACHINE Dec. 14, 1948.l

8 Sheets-Sheet '7 Filed April 11, 1947 l.. l.. RTHRocK SANDING MACHINEDe. 14, 194s.

Sheets-Sheet 8 Filed April 11, 1947 forney mounted a sprocket chain 46having rubber cleats or rubber blocks 41 on the outside surface thereoffor engaging the workpieces and feeding them through the apparatus. Thesprocket wheel 45 projects upwardly into an elongated slot 50 in the bedplate I3, and also the upper portion of the sprocket chain 46 hasmovement in this slot 50.

Rotatably mounted in bearing blocks 5 and 56, secured on the exteriorsurfaces of side members I and l2, is a shaft 51 on which is xedlymounted a sprocket wheel 58 and on which the sprocket chain 46 is alsomounted. The sprocket wheels 45 and 58 are of the same size so as tocause the upper portion of the sprocket chain to occupy a horizontalposition in the groove 50.

Secured to one edge of the bed plate i3 and to the side plate I2 andrising upwardly therefrom is a bracket 60 having a laterally projectingportion 6| which has a Vertical threaded hole therethrough in which isthreadably mounted a shaft 62 having a hand wheel 63 on its upper end.The lower end of this shaft 62 is shouldered (Figure 11) and penetratesan inverted U-shaped bracket 64 and a collar 65 rotatably confines thebracket 64 on the lower end of the shaft 62. The free ends of theinverted U-shaped bracket 64 have xedly mounted therein a shaft 66 onwhich is rotatably mounted a rubber-rimmed pressure wheel 61 which isadapted to press against the upper surfaces of the workpieces such as 2|and 22 which are being fed into the machine. Welded to the invertedU-shaped member 64 is a T-shaped arm 68 which is mounted for verticalsliding movement in a dove-tailed member 11 welded to the bracket 60.

Suitable legs 69 project upwardly from the table 22 and support aplatform 10 on which is mounted an electric motor 1| having Wires 12 and13 extending therefrom to any suitable source of electrical energy, notshown. The motor 1I has a shaft 14 extending therefrom on which is xedlymounted a pulley 15 and which has mounted thereon an endless abrasivebelt '16. This abrasive belt 16 has abrasive on the exterior surfacethereof and is usually sand paper or cloth or emery paper or cloth andthe like.

Secured to one edge of the bed plate I3 and to the side plate |2 is aplatform 19 having bearings 82 and 83 in which is rotatably mounted ashaft 8| having a pulley 80 thereon on which the abrasive belt 16 isalso mounted. The platform 19 has slidably mounted on its upper surfacea plate 84 on which the bearings 82 and 83 are mounted, and one edge ofthis plate 84 has a block 81 affixed thereto in which is rotatablymounted one end of 1 a threaded shaft 88 which is also threaded in abearing 89 extending upwardly from the platform 19. The threaded shaft88 has a hand wheel on one end thereof whereby the position of thepulley 80 can be adjusted longitudinally of the machine to take up anyslack in the endless ybelt 16.

There is also provided an idler pulley 92 rotatably mounted on a shaft93 which projects from one side of a vertically disposed bar 94 which isaffixed to one edge of the bed plate I3. Suitable braces 95 and 96 arealso secured to the vertically disposed bar 94 and to the edge of bedplate I3 and to the side member I2 for supporting the bar 94.

In order to apply the abrasive belt to the uneven surfaces of aworkpiece, certain pressure applying means are provided. It might bepointed out that the workpieces are usually of irregularly shapedmolding having projecting ribs 91 and depressions 98 between the ribsand a flexible endless belt is necessary and also suitable pressureapplying means are necessary to apply the belt to the surface to ybesanded while the belt is moving and also while the workpiece is movingat a much slower speed than the belt. It is of course evident that thesprocket chain 46 is travelling at a constant rate of speed and fromright-to-left in Figures 1 and 2 and the lower surface of the sandingbelt 16 is also travelling in a clockwise direction in Figure 1.

Projecting laterally from bar 94 is a shaft |00 which has keyed thereonby a suitable key |0I a hub member |02. The hub |02 has projecting fromone side thereof a portion |03 to which is secured by screws |04vertically disposed bars |05 and |66. Pivoted on bar |05 by means ofbolts |01 and |08 are links |09 and ||0. The vertically disposed bar |06has pivoted on screws |`|I and I I2, links I I3 and I4, respectively.The free ends of the links |09 and ||3 are pivoted by means of screws|I6 and ||1 to a bar IIB which is secured by any suitable means su-ch asscrews ||9 to a vertically disposed bar |20. The lower end of this bar|20 has likewise affixed thereto by means of screws |22 a similar bar|23 having its ends turned rearwardly towards the shaft |0l0 to whichthe free ends of links I|0 and I I4 are pivoted by means of screws |25and |26. surface of bar |20 near the lower end thereof is welded a plate|21 as shown in Figure 9, and also riveted to bar |23 is a flattenedU-shaped member |28. In the upper end of bar |20 is slidably secured oneend of a shaft |30 on which is pivotally mounted a bar |3I whichprojects downwardly and passes between the flattened U- shaped bar |28and the plate |21. Disposed halfway between the shaft |30 and theU-shaped bar |28 and welded to the vertically disposed bar |20 is a lugII5. An adjustment screw |2I, having a lock nut |24 thereon threadablypenetrates the lug |I5 and the bar |20 and the end of the screw I2|presses against the bar |3I for adjusting the same forwardly to raisethe forward end of block |48. The U-shaped bar |28 has passingtherethrough a pin I 34 which penetrates a bolt |33 which slidablypenetrates the bar |28 and disposed on this bolt I 23 are compressionsprings I 35 and |36 which tend to center the vertically disposed ybar|3|. The lower end of bar |3| has secured thereon by means of a bolt |40one-half of a socket I4| and secured to this half socket I4I by means ofa screw |43 is another half socket |42. The two sockets confine a ball|45 on the upper end of a stem |46 which has a platelike portion |41which is secured to a block |48 by means of screws |49.

The block |48 is preferably made of wood to prevent its heating up underthe friction of the belt. The lower surface of this block has grooves|5| therein and projections |52 therebetween which are the male portioncoinciding with the female portion which is the workpiece 2| or 22 beingoperated upon. This universal joint is preferable to allow the front endof the block |48 to move upwardly or downwardly to conform to the On theforward disposed above the table and having a pressure applying memberadapted to engage the upper surface of the lower reach of said abrasivebelt for holding the abrasive belt in contact with the upper surfaces ofthe workpieces as they are moved along said groove, the lower face ofthe pressure applying member being grooved to agree with theconfigurations of the upper surface of the workpieces being passed alongsaid groove, said pressure applying member being mounted for universalmovement on said pivoted framework for allowing its lower surface toconform to unevenness in the upper surface of the workpieces, saidpivoted frame having a lever arm extending therefrom and a weightadjustable along said lever arm for regulating the pressure of saidworkpiece, said pivoted frame also having a slidable rod associatedtherewith and means for securing said rod in adjusted position to holdthepressure applying means out of contact with the abrasive belt whendesired, said slidable rod have ing a tension spring associatedtherewith biased to counteract the weight on said lever to therebyprovide a resilient movable mounting for said pivoted framework. v

` 3. In a sanding machine for Ipolishing one side of a workpiece, meansfor feeding the workpieces longtudinallyof the machine, an abrasive beltextending longitudinally of the machine, an idler pulley near one end ofthe machine on which the abrasive belt is mounted, a motor driven pulleynear vthe other end of the machine on which the abrasive belt 'ismounted, a Second idler pulley disposed a substantial distance above themachine and over which the upper reach of the abrasive belt travels, apivoted framework mounted at one end above the framework, the other endof the pivoted framework having a pressure applying member adapted toengage said belt and force it into contact with the workpieces as theymove longitudinally of the machine, the pivoted framework havingextending therefrom a lever arm and a weight adjustably mounted on thelever arm for regulating the amount of pressure applied to the pressureapplying member to be in turn applied to the abrasive belt to hold it incontact with the upper surface of the workpieces, the lower surface ofthe pressure applying member being grooved to conform to the grooves andprojections on the upper surface of the workpiece,

a link having one end pivotally mounted to the free end of the pivotedframework and having its other end slidably mounted in a fixed portionof the machine, a tension spring associated with said link for normallyurging the free end of the y pivoted framework away from the abrasivebelt but not being sufficient to overcome the pressure exerted by theadjustable weight on said lever, and means associated with -said linkfor engaging the link when the pivoted framework is raised on its pivotto hold the pivoted framework in elevated position whereby its pressureapplying member will be held out of contact with the abrasive belt.l i

`-4. In a sanding machine having a table with a` groove extendinglongitudinally thereof through which workpieces are fed, an abrasivebelt for engaging the upper surface of the workpieces as they travelalong said groove, an idler pulley near one end of the table, a motordriven pulley near the other end of the table, a vertically disposed barintermediate the ends of vthe table having an idler pulley on1 its upperend, an abrasivebelt mounted on all of said pulleys, said verticallydisposed bar having a shaft projecting to force it into contact withthey yupper surfaces of the workpieces being passed along said groove,the free end of the framework having a, vertically disposed memberpivoted near its upper end 'on the framework and having its lower endslidably mounted on a transversely disposed bolt, compression springsdisposed on said bolt and on each side of the lower end of said pivotedmember for allowing lateral swinging movement of saidf pivoted member,the lower end of said pivoted member having a universal joint thereon, apressure applying member having a bearing extending from its uppersurface and secured in said universal bearing, the lower surface of saidpressure applying member being grooved to conform to the configurationsof the workpieces being passed along said groove, the pressureapplyingmember being adapted to engage the upper surface of the lowerreach of the abrasive belt for forcing the abrasive belt into contactwith q'the workpieces as they travel along said groove,

5. In a sanding machine having means fory feeding workpieces through themachine and anA abrasive belt for engaging the upper surfaces of theworkpieces as they pass through the machine, pressure applying means forAengaging the lower reach of said abrasive beltA for pressing it intocontact with the workpieces, comprising aframe.

rpivoted at one end and having a downwardly projecting member pivoted atits upper end in an upper portion of the free end of said pivoted frame,spring means for allowing lateral swinging l movement of the pivotedmember transversely of the path traveled by the workpieces, a ypressuremember having its lower surface grooved to conform to the grooves in theworkpieces being engaged by the abrasive belt, said pressure mem# berbeing pivoted to the lower end of the downwardly projecting member andbeing adapted to engage the upper surface of the lower reach of theabrasive to engage the upper surface of the lower reach of the abrasivebelt for forcing the abrasive belt into contact with the workpieces asthey travel through the machine, means for applying pressure to the freeend of the pivoted frame for in turn applying pressure to the workpieceto force it intol contact with the abrasive belt and to force theabrasive belt into contact with the workpieces passing through themachine, and means for latching the pivoted framework in raised positionto hold the workpiece out of contact with the abrasive belt.

LINVILLE L. ROTHROCK.

REFERENCES CITED le of this patent:

UNITED STATES PATENTS Number Name Date 470,794 Shempp Mar. 15, 18921,493,779 Humphreys May 13, 1924 1,927,330 Williams 1;.- Sept. 19, 19331,961,210 Fenton June 5, '1934 1,978,149 Stevenson Oct. 23, 19342,064,476 Johnson Dec. 15, 1936 2,227,865 Scott Jan. 7, 1941-v 2,338,644

Illmer et al. c 'Jan.,i4, .1944A

